Remove or change GuildChannel#updateOverwrite/#createOverwrite

[anandre]

Is your feature request related to a problem? Please describe.
GuildChannel#createOverwrite and GuildChannel#updateOverwrite are two methods that do the same thing. Duplicate methods doing the same thing are bad.

Describe the ideal solution
Remove one of the methods, or change them to do what their names suggest and only that - create makes a new overwrite, update changes an existing one.

Additional context
This is a breaking change.

[anandre]

tl;dr from server chat with @almostSouji - createOverwrite will make a new entry or set it to whatever's passed, updateOverwrite will make a new entry or edit an existing one to modify only what's passed. That's still... bad, in my opinion. The docs are not clear on this and makes it confusing for users. Could either refactor to one setOverwrites method as has been suggested before with an option to replace or modify in parameters, or enforce the separation of what they do per my second suggestion.

[almostSouji]

Isn't that already what it does?

Solved this confusion on discord, as we had discussions about this misunderstanding on my part before! The run down is:

• place or replace overwrite (if already exists)
• place or update existing overwrite based on provided flags (the other flags stay the same)